The present teachings are predicated upon providing an improved electromechanical parking brake system for a vehicle. Generally, an electromechanical parking brake system may include one or more brake pads and one or more Motor-on-Caliper units (MOC). The MOC may include a motor that is configured to move one or more brake pads against a rotor to create a clamping force (i.e., a parking brake force). To maintain the clamping force when electrical power to the electromechanical parking brake system is removed or interrupted, a low efficiency self-locking stage exists in the drive train of the electromechanical parking brake system. It is possible to increase the overall efficiency of the electromechanical parking brake system such that less energy is required to maintain the clamping force once the clamping force is generated. To maintain the clamping force, however, the MOC may need to be always energized because the low efficiency self-locking stage in the electromechanical parking brake system has been made more efficient and its self-locking property has been eliminated. In other words, a voltage and/or a current supply to the motor may be required to maintain the clamping force (i.e., to maintain the position of the one or more brake pads against the rotor) or else the electromechanical parking brake system may back drive, which may result in an undesirable and premature release of the clamping force. It may therefore be desirable to provide a magnetic clutch to lock the motor once the electromechanical parking brake system has created the clamping force (i.e., once the one or more brake pads have been moved against the rotor) so that the clamping force can be maintained without supplying a voltage and/or current to the motor. It may also be desirable to provide a magnetic clutch to change the efficiency of the MOC to be high efficiency when the motor is running (i.e., while the motor is moving the one or more brake pads towards or away from the rotor), and to be low efficiency when the motor is stopped (i.e., to maintain the clamping force).